Recently research on various systems for improving safety is ongoing in the automobile industry. In particular, a crisis avoidance system using an image sensor having an imaging apparatus has been developed. Specifically, a system which specifies an obstacle around a vehicle and which analyzes the movement of the obstacle based on images imaged by the imaging apparatus, whereby the vehicle avoids the obstacle, has been developed.
A system which extracts various information that is useful for investigating a cause of an accident by analyzing images before and after the accident has also been developed for cases when a crisis could not be avoided and an accident occurred. For example. Patent Document 1 discloses a system which obtains images before and after an accident using an imaging apparatus disposed at an intersection, and analyses the situations during the accident, such as the speed of a vehicle which caused the accident by analyzing these images. In this system, a plan view data, which is a data including only such stationary objects as a road surface and a crosswalk at an intersection of the accident site, is provided in advance, and images during the accident are projected on this plan view data, so as to analyze the situations of the accident. It is preferable to obtain three-dimensional information for analyzing the conditions of the accident. For example, three-dimensional information can be obtained by analyzing images input from many different angles, and it is useful to analyze the situations of the accident based on the three-dimensional information is useful. Patent Document 2, for example, discloses a technology which respectively transforms the coordinates of image data which are input from many different viewpoints, and connects them so as to be easily integrated into three-dimensional information.
The technology disclosed in Patent Document 1 can support only analyzing the situations of an accident at a location where a stationary camera, that is, an image apparatus, is installed, and of which the plan view data is provided in advance, therefore only accidents which occurred in predetermined locations can be handled. This means that the technology disclosed in Patent Document 1 cannot be applied to a camera installed on a vehicle, which is a moving body. The technology disclosed in Patent Document 2 is not a technology assuming the use for analyzing the situations of an accident, and can obtain only three-dimensional information of a stationary body. Therefore in the case of the technology disclosed in Patent Document 2, it is difficult to obtain three-dimensional information of a moving body, such as a vehicle and a pedestrian, even if three-dimensional information of such stationary bodies as a road surface, traffic lights and traffic signs, can be obtained.    Patent Document 1: Japanese Patent Application Laid-Open No. 2004-102426    Patent Document 2: Japanese Patent Application Laid-Open No. H7-174538